The lens capsule is a thickened basement membrane surrounding the lens which provides essential structural support for lens cells and mediates connection between the lens and the remainder of the eye. Lens capsule components also serve as survival, proliferation and differentiation signals for the attached lens cells although te relative contribution of each extracellular matrix protein found in the lens capsule to lens cell behavior is mostly uncharacterized. Integrins are major molecules mediating the communication between cells and their extracellular matrix. During the prior grant cycle we discovered that various integrins play essential roles in lens development as well as the pathogenesis of posterior capsular opacification (PCO), the major side effect of surgical cataract removal. However, the mechanisms by which integrins control lens development and the pathogenesis of PCO is not well understood. This application proposes to investigate the molecular mechanisms by which integrins control the fate decisions which regulate transitions from lens epithelial cells to fiber cells during development and pearl type PCO as well as transitions between epithelial cells and myofibroblasts during the process of fibrotic PCO development. These studies include investigations into the molecular function of fibronectin, an integrin ligand known to upregulate during PCO, in the pathogenesis of this condition. PUBLIC HEALTH RELEVANCE: The lens capsule is an understudied, but crucial regulator of lens biology. This application seeks to understand the molecular mechanisms underlying its fundamental role in both the regulation of normal lens biology and the conversion of lens epithelial cells to myofibroblasts, a main component of scar tissue. This work will provide fundamental insights into the pathogenesis of after-cataract (posterior capsular opacification), the major side effect of cataract surgery. This will allow us to identify additional molecular targets to prevent this condition which could result in better final visual outcomes for patients.